Description

Note:
This task depends on external libraries not included in the Apache Ant distribution.
See Library Dependencies
for more information.

The task may use the BSF scripting manager or the JSR 223 manager that
is included in JDK6 and higher. This is controlled by the manager
attribute. The JSR 223 scripting manager is indicated by "javax".

All items (tasks, targets, etc) of the running project are
accessible from the script, using either their name or
id attributes (as long as their names are considered
valid Java identifiers, that is).
This is controlled by the "setbeans" attribute of the task.
The name "project" is a pre-defined reference to the Project, which can be
used instead of the project name. The name "self" is a pre-defined reference to the actual
<script>-Task instance.From these objects you have access to the Ant Java API, see the
JavaDoc (especially for
Project and
Script) for more information.

Rhino provides a special construct - the JavaAdapter. With that you can
create an object which implements several interfaces, extends classes and for which you
can overwrite methods. Because this is an undocumented feature (yet), here is the link
to an explanation:
Groups@Google: "Rhino, enum.js, JavaAdapter?" by Norris Boyd in the newsgroup
netscape.public.mozilla.jseng.

If you are creating Targets programmatically, make sure you set the
Location to a useful value. In particular all targets should have
different location values.

Parameters

Attribute

Description

Required

language

The programming language the script is written in.
Must be a supported Apache BSF or JSR 223 language

Yes

manager

Since: Ant 1.7.
The script engine manager to use. This can have
one of three values ("auto", "bsf" or "javax").
The default value is "auto".

"bsf" use the BSF scripting manager to run
the language.

"javax" use the javax.scripting manager
to run the language. (This will only work for JDK6 and higher).

"auto" use the BSF engine if it exists,
otherwise use the javax.scripting manager.

No

src

The location of the script as a file, if not inline

No

setbeans

This attribute controls whether to set variables for
all properties, references and targets in the running script.
If this attribute is false, only the the "project" and "self" variables are set.
If this attribute is true all the variables are set. The default value of this
attribute is "true". Since Ant 1.7

No

classpath

The classpath to pass into the script. Since Ant 1.7

No

classpathref

The classpath to use, given as a
reference to a path defined elsewhere.
Since Ant 1.7

No

Parameters specified as nested elements

classpath

Since Ant 1.7

Script's classpath attribute is a
path-like structure and can also be set via a nested
<classpath> element.

If a classpath is set, it will be used as the current thread
context classloader, and
as the classloader given to the BSF manager.
This means that it can be used to specify
the classpath containing the language implementation for BSF
or for JSR 223 managers.
This can be useful if one wants
to keep ${user.home}/.ant/lib free of lots of scripting language
specific jar files.

NB: (Since Ant 1.7.1)
This classpath can be used to
specify the location of
the BSF jar file and/or languages
that have engines in the BSF jar file. This includes the
javascript, jython, netrexx and jacl languages.

We want to use the Java API. Because we don't want always typing the package signature
we do an import. Rhino knows two different methods for import statements: one for packages
and one for a single class. By default only the java packages are available, so
java.lang.System can be directly imported with importClass/importPackage.
For other packages you have to prefix the full classified name with Packages.
For example Ant's FileUtils class can be imported with
importClass(Packages.org.apache.tools.ant.util.FileUtils)
The <script> task populates the Project instance under
the name project, so we can use that reference. Another way is to use its given name
or getting its reference from the task itself.
The Project provides methods for accessing and setting properties, creating DataTypes and
Tasks and much more.
After creating a FileSet object we initialize that by calling its set-methods. Then we can
use that object like a normal Ant task (<copy> for example).
For getting the size of a file we instantiate a java.io.File. So we are using
normal Java API here.
Finally we use the <echo> task for producing the output. The task is not executed by
its execute() method, because the perform() method (implemented in Task itself) does the
appropriate logging before and after invoking execute().

Here is an example of using beanshell to create an ant
task. This task will add filesets and paths to a referenced
path. If the path does not exist, it will be created.